How 3D printing could help save Hong Kong’s coral

But these corals are under threat from pollution and rapid urban development.

Co-founded in 2020 by marine biology professor David Baker and PhD student Vriko Yu, the company hopes it can help make corals “more resilient” against climate change.

Rock bottom

Baker and Yu have been trying to restore coral at Hoi Ha Wan Marine Park since 2016 in partnership with the Agriculture, Fisheries and Conservation Department (AFCD).

The team needed to create a new “bottom” for the corals to grow on. Working with the university’s architecture department, they began developing an artificial coral reef using the university’s 3D printing facility.

A cuttlefish living in ArchiREEF’s clay reef tile test site in Hoi Ha Wan Marine Park, Hong Kong.

Vriko Yu

Once placed in the water, the team attach baby corals to the tile with non-toxic glue. The shape of the tile helps the corals grow upwards, attracting marine life that build their homes in the reefs.

More than 130 of these tiles were installed on the seabed in Hoi Ha Wan Marine Park in the summer of 2020, and archiREEF was born.

Commercializing restoration

The 3D-printed tiles are just one small part of archiREEF’s business model. After engaging corporate clients and governments to sponsor a restoration project, archiREEF will identify a site for restoration, install the reef tiles, and continue to manage the site for up to five years, monitoring the growth and the biodiversity of the reef.

Conventional artificial reefs, such as submerged concrete structures, often replace the function of the coral as a habitat for marine life, says Yu, whereas archiREEF wants to provide a “foundation” for the coral to grow on. Eventually, the coral will be strong enough to support itself without the tile — which can then be shattered by divers, or will naturally erode.

A diver positioning a 3D-printed terracotta tile on the sea floor.

CNN

An ‘innovative’ approach

However, Chui also adds that people need to be “realistic” about restoration and consider the cost and accessibility of technology. Places like Hong Kong also need more data on the efficacy of conservation efforts before it can be scaled in a meaningful way, she says, adding: “Restoration should be the last resort; we should protect before we restore.”

Conservation for everyone

Rescuing these reefs can help sustain the planet’s underwater ecosystems, such as seagrass meadows, which benefit from coral reefs, and are important carbon stores.

Fossil evidence points to corals living in Hong Kong for thousands of years.

Phil Thompson

ArchiREEF still has a way to go before scaling up. The team will observe the test site in Hoi Ha Wan for at least another two years to ensure the corals continue to thrive and survive natural disasters, such as typhoons. However, Yu says the results at the test site so far are promising: in the first six months of observations, four times more coral has survived on the clay tiles compared to conventional artificial reefs.

While archiREEF’s focus is currently on government and large corporate clients, it hopes to one day engage individuals in its projects, too.

“Restoration is currently restricted to conservation scientists,” Yu says. “But if we’re talking about stakeholders, it’s everybody.”